


Forming a Pact-Promise

by Silent_Observer_of_time



Series: Demons, Magic, Adventure and Shenanigans [5]
Category: Undertale (Video Game)
Genre: Alternate Universe - Demons, Alternate Universe - Monster Hunters, Alternate Universe - Supernatural Elements, Alternate Universe - Underfell, Childhood Memories, Demon!Sans - Freeform, Gen, Implied/Referenced Incest, Inappropriate Behavior, Inappropriate Humor, Innocent Papyrus, M/M, POV Papyrus, Papyrus Has Issues, Sans Being Sans, Sans Has Issues, Surprise Kissing, Underfell Papyrus, Underfell Sans
Language: English
Status: Completed
Published: 2017-01-11
Updated: 2017-01-12
Packaged: 2018-09-16 18:54:19
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 2
Words: 8,440
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/9285473
Author URL: https://archiveofourown.org/users/Silent_Observer_of_time/pseuds/Silent_Observer_of_time
Summary: Stuck alone and tied up to a tree, things can't get any worse for the rune knight until another demon came. Said demon is a lazy masochist who proclaims himself as his older brother which he accepted (Damn innocence in his youth!). Did he forget to mention this guy is the Second-strongest monster with only 1 HP? Probably not.[Ambiguous relationship between Underfell!Papyrus x Underfell!Sans]





	1. MAIN STORY

**Author's Note:**

> Sad there isn't much humor on this. ;n;

**Notes for the Chapter:**

> Read the next chapter for the EXTRA Scenes. Cameos and humor is on that way.

"Well at least it can't get any worse." Papyrus shrugged. Stretching his legs, the albino managed to get one of his boots. The other one was too far away because Mettaton tossed it before the demon teleported away. Demons and their teleport skills as the most basic skill, it's so unfair. Staring at the boot, Papyrus concentrates his energy, "Hmmm...."

...

"..." Papyrus sighs and waits patiently for Monster kid. The night isn't bad and he sensed no disturbance so it was okay to- Wait. what was that? Lords above, is that Sans? 'King Asgore no!'

"you called, boss?" His far away boot was lifted off the ground by another Demon Papyrus didn't want to meet in the middle of the nowhere. It was a supposed **Demon part of the Sloth Division Sans**. Because of a certain demon (Mettaton), Papyrus now knows who Sans is. The Prince of Darkness who is supposed to be the epitome of chaos and destruction. He should try getting out again. He doesn't want this skeleton demon pulling any dirty trick while he's bounded now, does he? Sans' eyes glowed in the dark as he stares at his 'younger brother.' Even if they were opposing sides, this demon will continue to see the rune knight as his baby brother. His baby brother who seems to heal him even when he's angry. Sans gave a grin.

'Oh God why do you curse me with such a FATE?' Papyrus pushes his head back and groaned in despair. He met Sans when he was a naive, five year-old who wanted to read books and become more helpful to his rider - Undyne. Yes. He was Undyne's dragon. Dragons age faster than Humans, but last longer than Humans so you could say Undyne was his primary Dragon rider and then if the gal got children, he'll still be their dragon. He also shouldn't forget the fact other beings can forge a pact and become his rider too. Funtastic! **The Organization** , filled with their quirky members, have well-kept secrets behind closed doors. One would be the fact **Undyne** is a half-mermaid who has to transform back to her mermaid self and swim at least once every three years or **Chara** as a half-demon who can't go inside the church and yet has to hear the mass every day hosted by King Asgore. Pure torture.

"i was sure you said my name..." Donned in a black biker jacket (probably? not sure but Papyrus recalls giving the demon a present when he was still naive and full of HOPE for the world) and matching red eyes, Sans scratch his back and yawned. Papyrus looks away and murmured. "I didn't call you, sleazebag. It was just a figment of your imagination!"

"but i sensed you called my name followed by a pimp-prosti demon. why else would i want to come here, ya know? i'm sure you've read in the books that most demons react when you say their names except well the **Demon Lord** who locks himself in his basement..." Sans struts around the tree the rune knight was bound to and whistled, staring right down at the annoyed rune knight. "i should probably **leaf** you to the wolves."

"I prefer you do that, you punning bastard!" Papyrus retorts, not even going to rely on the demon or beg for help. There was a reason why he was convinced Sans was part of the Sloth division. Sans did absolutely nothing to help or harm him except for his money because Papyrus sucks at games and can't determine if his opponent was cheating. What good was this demon anyways?! His childish mind must've been tampered with when it was young, seeing this demon as a cool brother figure. Sans sits down on his thigh, causing the rune knight to twitch at the weight, Sans rests more of his weight as emphasis.

"i wish i hadn't made that promise or i would've taken your SOUL right here, right now." Sans muttered, standing up to pick the red scarf tossed on the floor because of Mettaton's surprise attack. Heading back to Papyrus' side, Sans wraps the scarf back to the owner's neck. Papyrus scowls and moves away, he hates how Sans still treats him like a child. He was an adult and he can handle on his own.

_"What's this supposed to be?" An older albino male with crimson eyes asked, looking at a younger albino with similar eyes holding a box out to him. If no one knew any better, they would say the two were siblings. Dressed in a white loose shirt big enough to cover the child until his knees, the child placed the box on the older with eyes sparkling with excitement._

_"Papyrus learn from Undyne we give gifts to people we care about in gyftmas." The child waved his arms in the air as he talked. The older child, dressed in nobleman's outfit with matching ruffles and a red-black theme Victorian trend, opened the gift to see a black jacket. Looking back at the child, the red-eyed boy began to sweat hard. "y-you shouldn't have..."_

_"But you Papyrus friend! Papyrus promise to protect friends-?" The child claiming to be Papyrus blinks when the older child labelled as Sans kneeled down and hugged the child. Hugging Sans back, Papyrus hears Sans whisper. "i promise never to harm you too, lil' cinnabun. i'll even destroy half the world for you~"_

_"B-but Papyrus not food. Papyrus dra-gon and he strong~! Ra~!" The child began hitting the guy's back with his red mittens. Sans picks the child up, not bothered with the child's whining. Summoning out his wings, Sans grinned."let's find your gift, but you'll owe me when you grow up."_

_"No~! Papyrus no money and it dark tonight! demons come out in night!" Papyrus flails his arms with a single tear as Sans paid no heed to the child's cry._

"More like I wish you had never met me while I was a child..." Papyrus confessed, watching as Sans disappear and reappear on a tree in front of him for a short nap. Because he was a young and naive dragon puppy, Papyrus didn't know promises were prominent and spell-bound no matter what age or type the dragon was. "if i never found you, i'd never have such a cool bro but..."

"god i hate promises. it always **vines** me." Sans chuckled when he hears Papyrus hit the back of his head on the tree. It was a good thing Sans was also as spell-bound as he, unable to cast out magic to kill him. Papyrus groaned. "Can you go back to whatever realm you came from?!"

"nope. i like watching you suffer." Sans laughed, his black with red outline wings cover his body as the demon closed his eyes. For now, Sans thinks Papyrus' being MERCIFUL or being stupid for not killing him - the 1 HP Demon. It became a bad thing because when the rune knight's in his dragon form or even his human form, Papyrus' magic spells are deflected by some unknown barrier when he made a similar promise with Chara. Much to the Rune Knight's dismay, healing and support magic doubled when casted on the half-demon. Chara was the one who explained about Pacts and Promises for various magical entities. It was also the day Papyrus got a secondary Dragon rider - that being Chara. Chara also volunteered to be his partner from time to time. Undyne, Chara, MK and Doggo are the usual candidates. After a few minutes, Sans asked, "are you giving up hope for humanity yet?"

"nice legs by the way..." Sans had one eye open to look at him already raising his leg high enough to reach the metal clamp. "i can't wait to see your attire once you join the dark side and you're even gonna call me bro because i got a **gut** feeling you're a skeleton like me~"

"Screw off, Sans. You are not helping! Go take Mettaton instead, he needs someone to bother? I mean why else did he stalk me down for? He must be bored for a Lust demon." Papyrus was chipping the metal with his sharp heel on his boot. The whole atmosphere turned colder than the usual, Sans rests his back on the tree branch, "but bro, i'm a sloth demon for something. why else am i waiting for you to give up and join the dark side instead of killing your loved ones etchetera? i don't do chases, i wait 'till my prey tires out. 'sides, i promise you won't be seeing the nuts and bolts anytime soon. sumthing's gonna happen in the castle and it's probably a party with tons of fancy shindigs. you and chara can come over, we have chocolate~"

"NO! I do not party with my enemies and about your demon status..." Papyrus started, wanting to know whether Mettaton was right about Sans. Oh and to become a Demon, it usually involves the person getting killed where the dead person is filled with a certain emotion upon death. This emotion resurrects the human/creature into becoming a demon.

"whattaboudit?" Sans yawned, looking up at the crimson full moon. Seven negative emotions are categorized in the **Demon's Organization** : Pride, Wrath, Envy, Greed, Lust, Sloth and Gluttony. **Pride** is usually composed of the monarchs, the true demons from below. **Wrath** consists of the strongest demons who were once human and are generals of the monarchs. **Envy** and **Greed** are demons who don't side with either groups, usually pursuing their own interests. **Sloth** is composed of mediocre demons, but cannot be underestimated because they turn strong once motivation strikes them. Finally, the weakest and yet most gory creatures of the dark – **Gluttony** , most in numbers, they are used as a distraction and the most active night dwellers that consume the SOULs of the innocent. Papyrus asked, "Are you really the Prince of Darkness?"

"...." Sans turned silent. The Prince of Darkness is ranked second place in the scale of destruction, the first being the Demon Lord or head of the ' **Demons'**. It is **The Organization** 's task to eliminate the source of EVIL and LOVE which would equate to killing the Head of the following Demon Units. According to Undyne, Silence means yes. **Yes** means Undyne and he will have to kill Sans and said Demon will realize a huge White Almighty Dragon can't do shit towards him. Papyrus puts his leg down, tired from raising it.

"if i say yes, would you like me to convert you into a demon?" Sans asked, one of his crimson eye light stare right at the rune knight. Monarch Demons have the ability to infect a Human/entity into a Demon, this occurred with Chara and Frisk where they were the lucky duo who were able to escape the **Dark Castle**. However, the duo were infected and needed the blessing of the **Seraphim in the Organization** which back then was Toriel who gave birth to Asriel. Toriel's gone and Asriel took her place. Papyrus also has no idea what sort of life Sans has inside the dark realm, considering the demon's frequency in his room. He wasn't buying the because you're-my-younger-brother jig. He's old and can handle his own devices.

"No and answer the question without any strings attached!" Papyrus growled, Demon transformation takes about a week and even longer, depending on the WILL of the infected. This is a deadly curse as there is no CURE to the infection. The advantage here would be that direct infection increases your STATs and prolonged your SOUL LIFE. **The Organization** has no idea how many monarchs there are, but: The Demon Lord and the Prince of Darkness. Papyrus doesn't want to imagine a demon dragon would like like... Imagine how long he'll live?

"at least i tried..." Sans shrugged. Papyrus looked down, majority of the enchantments were wearing off so he'd finally be able to get out and be free from this demon. Worse news here was, the rune knight has to wait for two more hours before the sunrise because Demon attacks are weaker in the morning. If Sans is truly the Prince of Darkness, he can summon out entities and weird shit while sitting on the tree watching him get tired. It's like those stereotypical scenarios where the main character will gain back-up. Too bad, he's a supporting character and the guy in front of him is his... brother! The reason why **The Organization** gives them night missions is because of those picky Humans. "yeah. i'm the prince... no big deal."

"But that can't be right... You don't have money, you freeload in my bedroom or the library, you're too lazy to do anything, you have the **golden 1** in everything ("hey!" Sans frowned at that remark. The demon was in denial that his STATs are a permanent 1.) as well as the fact you don't give shit with what's going on unless it involves your mustard and living space!" Papyrus justified as he shook his legs a bit. Good. he can move them properly now. Papyrus looked down at his COOL DUDE Shirt. It has a scratch... NO! That demon will pay. "I see the cruelty part where you mess my life but what happened to your wealth?"

"ah. i got a lot of free time in my hands and i let gaster take care of the work which also led to him taking care of the money... when i feel like it, i'll destroy a castle or a village for fun and get some muns for work... but messing with your life is so much better than staying in the castle." Sans winked. Papyrus gave a bored expression, wiggling his hands wanting to strangle the demon. As if he read the rune knight's mind, Sans disappeared and reappeared right in front of the rune knight seating in between Papyrus' legs with a creepy grin. He rests his skull on the rune knight's forehead.

'I forgot this creature knows no FEAR.' Papyrus moved his head away when Sans gave him that grin, realizing his mistake where Sans was a masochist. Because Sans knows (but doesn't understand why) Papyrus' physical attacks heal him, Sans often caused the rune knight to get angry and hurt him, increasing Sans' HP beyond 1. "if i let you free, can we do **something naughty**  right now?"

"If I **accept**  your proposal, would you leave me alone when I'm busy in my room or when I'm in the shower?" Papyrus retorted back. He hoped the demon would accept his offer because he doesn't like stalkers in his life. Sans frowned and sat down with his legs under Papyrus' legs, pushing it down to rest on his. Papyrus' right eye twitched, this demon really is trying to piss him off. Sans' grin widened and answered. "i hate how you learned from your bro, but i did it for your own good... i wouldn't want **anything** hurting you. ah. it's more like **i  w i l l  n o t  let a n y o n e  t a k e  y o u r  S O U L  f r o m  m e** ."

"Yet you're too lazy to help me in my missions!" Papyrus replied, raising an eyebrow when Sans broke his restraints with a single swipe. Sans then rests his skull on his brother's forehead, giving him a forehead rub. Papyrus was about to ask why Sans was doing this until a glowing appendage came out from Sans' teeth and Sans tilts his head to allow it to enter the albino's mouth. Surprised, Papyrus felt Sans' hand on the back of his head as he goes deeper to get a taste. Papyrus muffled, trying to get out of the hold. As a half-dragon, he could taste the demon's emotion of **importance** and another darker, twisted emotion. It's toxic for a half-dragon who attends mass and uses holy magic in a daily basis. "S-Snnnsss!!"

"Gah!" Pushing Sans away, The taller albino was panting for air, covering his mouth with his sore wrists. Sans tsked, but he was smiling and looking healthier than usual (Oh that dick demon drank his magic didn't he? Papyrus did not see this coming.) "oh right, you're human. You guys need air to survive and all. my bad."

"W-warn me next time! And where did you learn that method anyways?" Papyrus spat out the taste in his mouth of mustard, metal and a weird unholy taste to see red substance. BLOOD?! It wasn't his blood right? He looked at Sans, glaring at the whistling, chirpy demon. Changing the topic, Sans looks at the broken cuffs and comments in a suggestive tone. "that gives me an idea on what we should do-"

"No! I will not tie you up, Sans! **The Organization** does not promote BDSM and I will not help you discover your other kinks in my room." Papyrus crawled to pick his dropped weapons. Sans  used telekinesis to tug the sword away and hugged the rear end of Papyrus. Sans was always so touchy, Papyrus wanted to summon out his tail and flick the demon to the other side. Oh wait. He can't reveal himself... Argh. Sans rests his head on his back. "they won't know~"

"But you and I will!" Papyrus can't sit or Sans will tickle him. He can't stab the demon or Sans would push it on his body and lap his blood. So! Papyrus threw a mustard bottle for Sans to catch, distracting the demon long enough (Sans loves Mustard more than his brother. A good thing.) for him to grab his levitating weapon. Fully armed and clothed, Papyrus remarked as he stood staring at the mustard-drinking demon. "Sans. Even if we realize both of us are sado-masochists, doesn't mean we should experiment on each other."

"you'll warm up to the idea someday, boss." Sans rolled his eyes still smiling as he vanished, leaving the rune knight alone. Papyrus' eyes widened, "Wait! You better not place some contraption in my room, you dirty demon!"

'NO~!' Papyrus was alone momentarily, frustrated that he has failed to ward a stalker away. It was his 'brother' but remembering the guy as the Prince of Darkness gives a whole twist all together. Turning to the exit, he hears a blonde squire call out to him. "P-Papyrus! You jerk! I was looking all over for you?! Undyne's gonna kill me if you died!"

"You're the slowpoke MK. Walk faster, will you?!" Papyrus ordered, continuous walking out of the forest. Pulling out a bar of chocolate, Papyrus bit on the sweet while his comrade called MK ran to catch up with him. Papyrus hoped he wouldn't find Sans in his room bringing weird items like last time. 'Nah. Sans would definitely do just that... Idiotic Demon! If only I could kill you…!'

**Notes for the Chapter:**

> Sans and Papyrus' relationship is weird because Sans knows Demon culture while Papyrus is an orphan tool. Sans will be further explained in another one-shot. [Blame bad parenting~ May hint to Sans/Gaster]


	2. EXTRA/FAIL SCENES [HUMOR AND SEXUAL? CONTENT]

**Summary for the Chapter:**

> Sans and Papyrus are the usual while the cameos are back again... LOL

[SWITCHING ROLES]

"..." Sans blinked and found himself in shackles, tied to a tree nearly naked. Looking at the incoming presence, Sans' eyes widened to see his brother wearing a black and red tailcoat matching with a black top hat as well as black and red outlined wings behind him. Sans whistled and winks at the demon. "nice look there baby bro~"

"Sans! You ruined my intro!" Papyrus stomped his feet and Sans laughed. "yeah yeah. so can we get back to our original positions in this story?"

"Fine." Papyrus fluttered his wings before snapping his fingers, breaking the binds on his older brother.

[CUT!]

* * *

 

[BOOTS]

"Well at least it can't get any worse." Papyrus shrugged. Stretching his legs to grab one of his boots, Papyrus paused when he saw both of his boots missing. "...Sans why?"

"i declare these boots as..." Sans was wearing them as Papyrus was giving him the stare stating you-got-to-be-kidding-with-me? "pimp boots!"

"SANS!" Papyrus screamed and Sans walked around with the boots.

[CUT!]

"I wanna try those boots too!" Asriel stood up with grabby hands but Chara pushes them down. "No! Stay down and Sans, place those boots back where it belongs!"

[TAKE ONE!]

"Well at least it can't get any worse." Papyrus shrugged. Stretching his legs to grab one of his boots, Papyrus paused when he heard weird sounds coming from the bushes. "Is that Undyne and Alphys?"

[CUT!]

"get a room!" Chara screamed and kicked the unknown entities within the bushes. Sans came quite late with a bottle of mustard. Papyrus and Sans stared at each other, Papyrus mutters, "Where are your wings?"

"..." Sans looks behind him and replied, "i'll summon it out later."

[CHANGE SCENE!]

"..." Papyrus sighs, waiting for Sans to douche over and then he saw something up at the sky. Papyrus blurts out, "METTATON?!"

 "I'm back baby-" Mettaton was stabbed by a very gigantic bone and Papyrus had to look down to see a pissed Sans. "Oh. Hi Sans."

[TAKE ONE!]

"..." Papyrus sighs, waiting for help until he sensed something. Papyrus accidentally blurts out, "Lords above, why are you here Sans?!"

"...pft." Sans laughed even before he came over and Papyrus slung his head to the ground.

 

[CUT!]

"Let's try not to greet Sans okay Papyrus?" Alphys has a sweat drop as Sans continues to laugh. Papyrus merely nodded as Frisk went over with coffee.

* * *

[SAYING MY NAME]

"i was sure you said my name..." Sans scratch his back and yawned. Papyrus looks away and murmured. "I didn't call you, sleazebag. I was calling Chara!"

"boss... no~" Sans felt defeated as Chara came out with Asriel. "In your face, Sansy!"

[TAKE ONE!]

"i was sure you said my name..." Sans scratch his back and yawned. Papyrus looks away and murmured. "I didn't call you, sleazebag-! Sans don't give me that look...."

"but you called for me..." Sans has those starry eyes. Papyrus moves away in disgust as Sans went over to his brother and gave a hug. "love you too boss~"

"IT STINGS!" Papyrus screamed and Sans still hugs.

[CUT!]

"You can stop hugging now..." Asriel has a sweat drop but the older brother remain firm.

_Reality..._

"accept the love boss~!" Sans coerced, crushing Papyrus' with his arms. Papyrus struggles to respond, trying to get out of the restraints. "N-Never!"

* * *

[SAYING MY NAME PT 2]

"but i sensed you called my name followed by a pimp-prosti demon. why else would i want to come here, ya know? i'm sure you've read in the books that most demons react when you say their names except well the Demon Lord who locks himself in his basement..." Sans struts around the tree the rune knight was bound to and paused when he saw Frisk come out.

"kid?" Sans asked but Frisk screams at him. "I always say your name in my dreams and you don't come to me in bed!"

"..." Chara was behind Frisk and did a slicing motion to the neck. Sans sweats, "crap."

[CUT!]

"That was uncalled for." Papyrus said, but he had a smirk as he nudged Sans. "You have an admirer-Ow!"

"s-shut up!" Sans sat down and crushed the rib cage of his brother with the fake wings. Chara was pulling Frisk away as they cry silently, comforting them saying. "Frisk, you don't say your Freudian slip out loud."

"But I love him Chara!" Frisk confessed and Chara paused. Still tied up, Papyrus' eyes widened from the revelation and leaned close to his brother with a whisper. "Sans. Run while you still can or Chara's coming for you."

"...i just want you too know that... i vomited on the couch today." Sans vanished before Papyrus could restraint him for Chara's death sentence.

[TAKE ONE!]

"but i sensed you called my name followed by a pimp-prosti demon. why else would i want to come here, ya know? i'm sure you've read in the books that most demons react when you say their names except well the Demon Lord who locks himself in his basement..." Sans struts around the tree the rune knight was bound to. Papyrus looks at Sans and asked in a curious expression. "What about your fans who fantasize about you in their dreams or just screams your name for no reason?"

"... i do a **gaster**." Sans grinned and Papyrus nodded in agreement. From the mist, Gaster comes out surprising the two as he screamed in anger. "What is that supposed to mean?!"

[CUT!]

* * *

[I DON'T MEAN IT]

"i should probably **leaf** you to the wolves." Sans joked but after a while, began to tear up. "i would never leave you boss!"

"SANS!" Papyrus whined when Sans gave him another hug.

[CUT!]

"That's adorable~" Frisk confessed and Chara simply face palmed.

[TAKE ONE...]

"i should probably **leaf** you to the wolves." Sans joked but Papyrus retorts, "I prefer you do that, you punning bastard! You'll just get in my way like that one time-"

[CUT!]

"..." Papyrus and Sans stared at each other and Frisk had to be the one to cut. Chara was staring at Frisk judgingly, replying. "Yeah Frisk. Like that one story where you were gonna kill Sans first but Papyrus died instea-"

"Shut up Chara." Frisk stuffs a cinnabun in their friend's mouth.

* * *

[SLIPPED IN MY MIND]

"i wish i hadn't made that promise or i would've taken your virginity right here, right now." Sans muttered and paused when he saw Papyrus' eyes wide open. "ah crap."

[TAKE ONE!]

"i wish i hadn't made that promise or i would've taken your SOUL right here, right now." Sans muttered, standing up to pick the red scarf tossed on the floor.

Heading back to Papyrus' side, Sans wraps the scarf to gag his brother. Looking at his work, Sans nodded. "now we're ready."

[TAKE TWO!]

"i wish i hadn't made that promise or i would've taken your SOUL right here, right now." Sans muttered, standing up to pick the red scarf tossed on the floor.

Heading back to Papyrus' side, Sans wraps the scarf back to the owner's neck and made a ribbon tie. Papyrus scowled at him as Sans nodded. "this is a present worth taking."

[TAKE THREE!]

"i wish i hadn't made that promise or i would've taken your SOUL right here, right now." Sans muttered, standing up to pick the red scarf tossed on the floor.

Heading back to Papyrus' side, Sans wraps the scarf on to Papyrus face and leans over to bite the neck.

[CUT!]

"You are not a vampire!" Chara screamed as she held Undyne in place. Frisk had a camcorder and gave a thumbs-up. Blinded, Papyrus doesn't understand what's going on as Sans rests on his shoulder and gave a pose for his friend.

* * *

 [INNOCENCE WITH YOUNG PAPYRUS]

"Papyrus learn from Undyne we give gifts to people we care about in gyftmas!" Young Papyrus waved his arms as he talked. Sans knelt down and whispered, "do you know what else people do in gyftmas?"

"?" Papyrus wondered and Sans picked him over for a chaste kiss.

[CUT!]

"How dare you?!" Undyne cursed as the female went forward with her spear. Sans held the young Papyrus close, grinning. "sorry babe, but he's mine."

"I want to hug a cute Papyrus!" Frisk has a tear, but Chara held them back. "Not yet my friend... Not yet."

[TAKE ONE!]

"Papyrus learn from Undyne we give gifts to people we care about in gyftmas!" Young Papyrus waved his arms as he talked. Sans knelt down and whispered, "do you know what i want more than anything, bro?"

"?" Papyrus wondered and Sans picked him over with a grin. " **i  w a n t  y o u r  s o u l . . .** "

[C-CHANGE SCENE!]

"But you Papyrus friend! Papyrus promise to protect friends-?" The child claiming to be Papyrus blinks when Sans knelt down and hugged the child. Hugging the child, Sans whisper. "let's sign a contract so it'll be just you and me against the world~"

[TAKE ONE!]

"But you Papyrus friend! Papyrus promise to protect friends-?" The child claiming to be Papyrus blinks when Sans knelt down and hugged the child. Hugging the child, Sans asked. "i thought you saw me as a brother?"

"YOU ARE MY BROTHER, SANS! THE COOLEST BROTHER I COULD EVER HAVE~" Papyrus cheered.

[CUT!]

"I can't... It's too much even for me." Chara cursed and pulled their knife. "We have to kill him."

"Chara No!" Frisk pulls the maniac away while Sans was cuddling his brother.

[CHANGE SCENE!]

"B-but Papyrus not food. Papyrus dra-gon and he strong~! Ra~!" The child began hitting the guy's back with his red mittens. Sans picks the child up, not bothered with the child's whining. Summoning out his wings, Sans hummed."time to bring you back with me~"

[CUT!]

"Undyne! Chara! No!" Frisk couldn't stop the two as they rushed forward. "Sans! Run before it's too late!"

"shit." Sans vanished at the last moment.

[CHANGE SCENE!]

"No~! Papyrus no money and it dark tonight! demons come out in night!" Papyrus flails his arms with a single tear. Sans pats his brother's back, "no worry bro, the only demon who's gonna touch you is me and me alone~"

[CUT!]

"Sans is pretty protective of lil' Paps, isn't he?" Chara stares at Frisk who nods. Frisk took a picture, Sans was cuddling his brother again. "Do we have any more of that youth potion because I really want to take care of the Papyrus double."

"It's for the other story!" Alphys argued as she was fixing Mettaton's chest plate. 

* * *

 [WEIGHT CONCERNS]

"More like I wish you had never met me while I was a child..." Papyrus confessed, watching as Sans disappear and reappear on a tree in front of him for a short nap. However, the tree branch he rested on snapped, causing the skeleton to fall and die. Papyrus' eyes turn wide open. "SKELETON DOWN! SKELETON DOWN!"

[CUT!]

"Stupid smiley bag and his HP problem." Chara cursed while Frisk went forward with bandages.

[TAKE ONE!]

"More like I wish you had never met me while I was a child..." Papyrus confessed, watching as Sans disappear and reappear on a tree in front of him for a short nap.

Sans turned silent, Papyrus looked over and groaned. "Sans! It's part of the script."

"you could have meant it..." Sans was crying and the casts had to untie Papyrus to calm him down.

[TAKE TWO!]

"More like I wish you had never met me while I was a child..." Papyrus confessed, watching as Sans disappear and reappear on a tree in front of him for a short nap.

Sans turned silent. "if i never found you, i'd never have to destroy so many villages and kill so many people...paps? oh fuck! i didn't mean that boss! don't be sad!"

"You killed so many people who could have made my life easier?" Papyrus bowed his head with tears and Sans had to go down to wipe his brother's tears. "boss~ come on."

 [CHANGE SCENE!]

"god i hate promises. it always **vines** me." Sans chuckled when he hears Papyrus hit the back of his head on the tree.

Papyrus groaned. "Can you go back to whatever realm you came from?!"

"nope. i like seeing you tied up ready to be fucked over." Sans laughed and closed his eyes. However, Papyrus removed his bounds with an annoyed look. Sensing the disturbance, Sans immediately backs away. "uh-oh."

[CUT!]

"You gone too far, runt!" Papyrus summoned out his bones and Sans starts running. 'fuck fuck fuck fuck!'

* * *

[CONFESSION]

Waiting together, Sans asked as he has that distant look. "are you giving up hope for humanity yet?"

"YES." Papyrus agreed.

[TAKE ONE!]

Sans asked, one eye staring at Papyrus. "are you giving up hope for humanity yet?"

"YES." Papyrus reaffirmed.

[TAKE TWO!]

Sans asked, this time smiling. "are you giving up hope for humanity yet?"

"YES!" Papyrus screamed.

[CUT!]

"Why won't you say NO!" Frisk asked. Both skeletons stare at the Human and Papyrus comments. "You and your genocidal tendencies?"

"...Burn." Chara chuckled as Frisk weeps on the floor.

* * *

[LEGS AND REALIZATION]

"nice legs by the way..." Sans had one eye open to look at him already raising his leg high enough to reach the metal clamp. "i can't wait to hold it as i fuck you over on the bed."

[CUT!]

"you're even gonna scream my name as i fill you with my seed." Sans continued and Papyrus had to bang his head on the tree. Sans chuckled, "always wanted to say that."

"Too bad you ain't gonna!" Chara rolls her eyes. Undyne, however, points out. "But Sans is going to do this with Frisk in one script."

"...What?" Chara asked and Sans begins to back away with sweat pouring down his skull. 'not again!'

[TAKE ONE!]

"nice legs by the way..." Sans had one eye open to look at him already raising his leg high enough to reach the metal clamp. "i can't wait to see your attire once you join the dark side and you're even gonna call me boss-"

"Sans no." Papyrus warned, Sans already approaching him with glinted eyes. "Sans yes."

[CUT!]

"Sans no!" Frisk argued but Sans squirmed from the Human's grip. "but it's gonna be the first time! i need to do this! i want to be the boss this time!"

"You can do it Human! I believe in you for my safety!" Papyrus urged as Frisk drags Sans away. Chara was shaking her head and followed their partner in the backstage.

* * *

[METTATON]

"Screw off, Sans. You are not helping! Go take Mettaton instead, he needs someone to bother? I mean why else did he stalk me down for? He must be bored for a Lust demon." Papyrus was chipping the metal with his sharp heel on his boot.

The whole atmosphere turned colder than the usual, Sans sat up. "time to murder a certain demon then."

[TAKE ONE!]

"Screw off, Sans. You are not helping! Go take Mettaton instead, he needs someone to bother? I mean why else did he stalk me down for? He must be bored for a Lust demon." Papyrus was chipping the metal with his sharp heel on his boot.

The whole atmosphere turned colder than the usual, Sans gave a wink. "but i don't want anyone but you boss~"

"Lies!" Frisk declared and Chara had to take over.

[TAKE TWO!]

"Screw off, Sans. You are not helping! Go take Mettaton instead, he needs someone to bother? I mean why else did he stalk me down for? He must be bored for a Lust demon." Papyrus was (getting tired of) chipping the metal with his sharp heel on his boot.

The whole atmosphere turned colder than the usual, Sans placed his phalanges on his teeth. "but i'm not into robotic pricks.."

[CUT!]

"Say that again! I dare you!" Mettaton cursed and Sans complied. "that's right, mtt. you are a robot who is both a bastard and a bitch!"

"Sans. Let's not start a fight..." Papyrus gets ignored as Sans and Mettaton initiates a FIGHT with Undyne, Alphys, Chara, Frisk, Asriel and Flowey as the audience.

* * *

[ANYTHING FOR CHOCOLATE]

"but bro, i'm a sloth demon for something. why else am i waiting for you to give up and join the dark side instead of killing your loved ones etchetera? i don't do chases, i wait 'till my prey tires out. 'sides, i promise you won't be seeing the nuts and bolts anytime soon. sumthing's gonna happen in the castle and it's probably a party with tons of fancy shindigs. you and chara can come over, we have chocolate~" Sans confessed and before Papyrus could reply, Chara came out from the woods and shouted. "We agree!"

"Chara!" Papyrus screamed. Sans and Chara did high five. Sans grinned at Papyrus. "Welcome to the dark side, buddy~"

"NOOO~!" Papyrus screamed in despair as Chara and Sans discuss about the party's requirements.

[CUT!]

* * *

[DEMON STATUS]

"NO! I do not party with my enemies and about your demon status..." Papyrus started. Sans yawned, looking up at the crimson full moon. "whattaboudit?"

Papyrus asked, "Are you really that great with that one HP?"

"...." Sans turned silent, Gaster blasters hovered behind him.

"I REGRET NOTHING!" Papyrus declared as his last words.

[TAKE ONE!]

"NO! I do not party with my enemies and about your demon status..." Papyrus started. Sans yawned, looking up at the crimson full moon. "whattaboudit?"

Papyrus asked, "Are you really the Prince of Darkness?"

"...." Sans turned silent and grinned. " **not for long** ~"

_Meanwhile..._

"ACHOO!" Gaster sneezed and looked around. "Someone's plotting for my death again..."

[TAKE TWO!]

"NO! I do not party with my enemies and about your demon status..." Papyrus started. Sans yawned, looking up at the crimson full moon. "whattaboudit?"

Papyrus asked, "Are you really the Princess of Darkness-crap wait Sans. I didn't mean it!"

"...." Sans turned silent and opened his mouth, walking towards the defenseless rune knight. "i'm going to fuck you now."

Papyrus screamed. "My ass is not ready!"

[TAKE THREE!]

"NO! I do not party with my enemies and about your demon status..." Papyrus started. Sans yawned, looking up at the crimson full moon. "whattaboudit?"

Papyrus asked, "Are you really the Prince of Darkness?"

"...." Sans turned silent and smiled. "nah. i'm your brother so if i'm a prince, you're also a prince."

"...!" Papyrus gasped.

_Meanwhile..._

On the bushes, Chara and Undyne face palmed while Frisk and Asriel snickered.

[CUT!]

* * *

 [NOT TAKING NO FOR AN ANSWER]

"if i say yes, would you like me to convert you into a demon?" Sans asked, one of his crimson eye light stare right at the rune knight. Papyrus growled, "No and answer the question without any strings attached!"

"who said you had a choice?" Sans grinned and came close to Papyrus. " **n o w  s h o w  m e  y o u r  s o u l . . .** "

[CUT!]

* * *

[ACCEPTANCE]

Sans shrugged. "yeah. i'm the prince... no big deal."

""But that can't be right... You don't have money, you freeload in my bedroom or the library, you're too lazy to do anything, you have the **golden 1** in everything as well as the fact you don't give shit with what's going on unless it involves your mustard and living space!" Papyrus justified as he shook his legs a bit.

"true..." Sans nodded and a knife nearly stabbed the skeleton on the skull

[CUT!]

"Follow the script you idiot!" Chara screamed and it was Flowey who wrapped its vines around the Human. Frisk was busy eating butterscotch pie to do anything. 

* * *

[CONFESSIONS PT 2]

"I see the cruelty part where you mess my life but what happened to your wealth?" Papyrus tilts his head.

Sans sulks, "gaster took all of it like a bastard and would only let me have it if i kill humans... i had to do side jobs just to get your gifts boss..."

"... I don't know what to say." Papyrus looks at the side and another knife nearly stabs Sans.

[CUT!]

* * *

[BROTHERS BEING BROTHERS] 

After Sans wink, Papyrus yawned and had a question mark when he saw Chara ready to stab him with a knife. "Wait what?"

"boss. your line!" Sans groaned, using telekinesis to alter the direction of the knife toss.

[TAKE ONE]

After Sans wink, Papyrus twitched and made hand gestures which made Sans appear immediately in front of him. While the brother's had a little nonverbal conversation how this is not about sex, Chara looks over to Frisk.

"Papyrus knows sign language?" Chara has their eye brow raised. Frisk nodded, pointing at a tearful scientist. "He thought them."

"Better than nothing wait a minute!" Chara looks over to see Sans raising Papyrus' lower body to rest on his. "SANS NO!" 

* * *

[SEXUAL SCENE NEEDS TO BE TONED DOWN]

Sans asked with a grin, "if i let you free, can i fuck you?"

"NO." Papyrus refused but Sans whistles, "who said i take no for an answer?"

[TAKE ONE!]

Sans asked with a grin, "if i let you free, can i fuck you?"

"NO." Papyrus refused but Sans tries again. "how about now?"

"NO."

"now?"

"NEVER."

"what about now?"

"...Maybe?"

"now?"

"Fine! But if you **duck** me, leave me alone and go back once you came?" Papyrus retorted back, censoring the 'vile' word. Sans answered, "i hate how you gotta censor yourself, but i'm your older brother... i wouldn't want **anything** hurting you or taking your body away from me." 

[CUT!]

"Why did it take us so long to stop them? They were already deviating from script!" Frisk complained but Chara was laughing at how Papyrus reeling away from Sans.

"but you said yes!" Sans muttered, but Papyrus screamed. "Because you are an ass for wanting some fucks!"

"We should tweak the script..." Alphys nodded. Undyne stares at the story warning. "Yeah...yeah we should."

[CHANGE SCENE!]

Sans asked with a grin, "if i let you free, can we do **something naughty** right now?"

"If I accept your proposal, would you leave me alone when I'm busy in my room or when I'm in the shower?" Papyrus retorted back, wincing slightly when Sans pushes Papyrus' legs onto his.

Sans' grin widened and answered. "you mean your jerking session? sure. heat session? never."

[TAKE ONE!]

Sans asked with a grin, "if i let you free, can we do **something naughty** right now?"

"If I accept your proposal, would you leave me alone when I'm busy in my room or when I'm in the shower?" Papyrus retorted back, wincing slightly when Sans pushes Papyrus' legs onto his.

Sans' grin widened and answered. "sure but i'll make sure everyone knows   **y o u  a r e  m i n e .** "

[CHANGE SCENE!]

"Yet you're too lazy to help me in my missions!" Papyrus replied, raising an eyebrow when Sans didn't break his restraints with a single swipe. "Sans what are you-"

"Nyeh~!" Papyrus whined when Sans placed his hands underneath his shirt. "S-Saaaannnsss~!!"

[TAKE ONE!]

"Yet you're too lazy to help me in my missions!" Papyrus replied, raising an eyebrow when Sans didn't broke his restraints with a single swipe. Sans then rests his skull on his brother's forehead and tilts his head.

"and i got too lazy to kiss you." Sans confessed and Papyrus laughed.

[CUT!]

"Really Sans?" Alphys face palmed and Sans fell asleep on his brother's chest. Papyrus shrugged and pushes Sans off him.

* * *

[CATCHING THE HEAT!]

"?" Papyrus was about to ask why Sans was doing this until he realized he should not have done so. By opening his mouth, Sans gained access to his mouth to perform a kiss. It also wasn't to the albino's joy when Sans gripped the back of his head painfully to pull him closer, feeling the slimy magical tongue explore his mouth and even the back of his throat.

The thing that went overboard was when Papyrus could taste the demon's emotion of **need**  and crap! Not only was the other twisted emotion toxic for him who attends mass and uses holy magic in a daily basis, but this demon was in heat and it was bad, really bad. "S-Snnnsss!!"

"Gah!" Pushing Sans away, The taller albino was panting for air. Sans growled, his wings slightly raised. He was having none of that, pushing the albino back down for another heated kiss. The demon even destroyed the trees beside them just to get closer to the rune knight. Papyrus pulls away, trying to get the heat-hazed demon off him. Sans placed his hand on the ground to cast out another dark magic spell to paralyze his victim, rubbing feverishly at him. It seems friction works well for skeleton demons and his clothes are being dispatched as he's paralyzed. 'Should've wore a chastity belt today.'

"S-sans?" Papyrus whined and knew Sans was going overboard with the hip grinding. It was making him feel aroused and he can sense a dick from the demon. Well fuck this! First a robotic incubus and now your skeleton brother, this can't get any worse? Sans leaving trails of hickeys his neck (And the scarf is gone too apparently), whispering in a loving tone. "mine~"

[CUT!]

"S-sans~" Papyrus struggled but Sans was far gone from reasoning and Papyrus' barriers begin to fall down. Sans plans on tearing it apart even if the other party refuses.

_Meanwhile..._

"You said Sans' heat was over." Chara looks at Frisk. Frisk looks from side to side, looking back. "He must have lied to me?"

"I think we should save Papyrus..." Undyne continues to stare at the duo and looks back at them. "But have you guys ever tried taking a dom away from his sub?"

"...Let's wait it out instead! Want to watch some movies?" Alphys asked, cleaning her glasses as she stared at the others. Chara and Frisk stared at the hearts from the area and looks back. "Sure."

_After the mad session..._

"We could have added that and no one would be wiser!" Undyne suggested but the two Humans shook their head.

"Too much sex scenes for one story. This is more of a crack fic." Frisk explained. Chara looks over to see Sans cuddled close to Papyrus. Papyrus who's too tired to even move.

"I'm going to be sore after this..." Papyrus admits, not even able to have enough energy to stand. Chara was about to give him chocolate until Sans' wings moved. Chara moves away and stared at Papyrus.

"It's not me, it's your sleepy brother." Chara replied and Papyrus laid on the ground until Sans woke up.

...

Fortunately, Sans promised the heat has dissipated... temporarily

...

Fortunately, Papyrus is forgiving on his brother's actions... artificially

...

And in spite of all this, they continued the play...

* * *

[TRUTHS] 

"oh right, you're human. You guys need air to survive and all. my bad." Sans grinned. Papyrus spat out some red substance (it's actually Sans' cum) "At least I can survive longer in bed."

"ready for round two then?" Sans grinned and Undyne had to be the one to toss Sans away from the taller skeleton. Sans vanished and came back beside Papyrus. "boss started it."

[CUT!]

"Oh. So I can't flirt with you or I'll get the bone?" Papyrus asked and Sans gave him a grin. "yeah."

"Fine. Let's start again-" Papyrus crossed his arms, but then Sans went on all fours and leaned close to him. Inches apart, Sans asked. "but everything you do is eye-catching~"

"Frisk!" Papyrus screamed for help. Moving away slightly (not to show fear because that's also attractive for Sans), finally seeing the return of the **lust** in the skeleton's eyes, "I am challenging your title and Sans is the judge!"

"I accept the challenge." Frisk went forward and Chara had to bring them back away.

* * *

 

[THIRD PARTY]

"W-warn me next time! And where did you learn that method anyways?" Papyrus spat out red substance. He looked at Sans, glaring at the whistling, chirpy demon.

Sans grinned, "learned it from anime."

"YES!" Alphys shouted and covered her mouth.

[CUT!]

* * *

[WHAT MUST HAVE HAPPENED]

"No! I will not tie you up, Sans! The Organization does not promote BDSM and I will not help you discover your other kinks in my room." Papyrus crawled to pick his dropped weapons. Sans used telekinesis to tug the sword away and hugged the rear end of Papyrus.

Sans rests his head on his back. "if you won't tie me up, i will~"

[TAKE ONE!]

"No! I will not tie you up, Sans! The Organization does not promote BDSM and I will not help you discover your other kinks in my room." Papyrus crawled to pick his dropped weapons. Sans used telekinesis to tug the sword away and hugged the rear end of Papyrus.

Sans rests his head on his back, Papyrus yelped at the familiar (bad feeling) as Sans rubbed his pelvic on the albino's ass. "god. i want to fuck you so badly~"

[CUT!]

"NO! SANS." Papyrus screamed as he felt Sans' hands tug him closer to the ghost dick. Sans presses his face onto his brother's back, grind-humping his brother.

"Maybe we should move the date?" Alphys asked, but Frisk was looking at their schedule. "No. Sans will be busy with the other stories."

"Guys... HELP Please?" Papyrus doesn't know what to do. If he sits down, Sans would feel more pressure on his groin and activate his heat. If he kicks him, Sans would use his legs and drag him down to the ground where round two might commence (NO!) Papyrus opted for the most cowardly thing he can do, talking. "Sans? When are you going to stop humping me?"

"boss~" Sans ignored him, contented with the feeling of his brother's presence (more like that ass).

* * *

[DON'T TALK WHEN YOU'RE DRINKING] 

Fully armed and clothed, Papyrus remarked as he stood staring at the mustard-drinking demon. "Sans. Even if we realize both of us are sado-masochists, doesn't mean we should experiment on each other."

"hmhmmhhmjjh, boss." Sans smiled and Papyrus had to face palm.

[CUT!]

* * *

 

[PROBLEMS AGAIN]

When Sans vanished, Papyrus' eyes widened, "Wait! You better not touch my Favorite Bedtime story book, you dirty demon!"

[CUT!]

"Why would Sans get your Peek a boo with Fluffy Bunny?" Undyne asked with a raised eyebrow. Papyrus crossed his arms, "I need that to go to sleep."

_Meanwhile..._

"Sans. Why do you take the book?" Frisk asked. Sans goes quiet before whispering. "I take it as hostage so boss would let me in his room and let me sleep with him."

"Nightmares?"

"nightmares and more."

"..." Frisk stared at Sans and raised their hand. "I can help you-"

"NO." Chara refused as they covered Frisk's mouth. "I know you're nice, but helping the comedian isn't going to be your bucket list as long as I'm around. Got it?"

"K..." Frisk nodded. When Chara dragged Sans back to stage, Frisk grinned. "Too bad I turned into a demon, huh Chara?"

* * *

 

[TRIPPING]

"P-Papyrus! You jerk! I was looking all over for you?! Undyne's gonna kill me if you di-IIEEED!" MK fell to the ground in a spectacular way. Instead of saying his lines, Papyrus covered his face and laughed.

"S-Stop laughing jerk!" MK has tears in his eyes.

[CUT!]

"I-I apologize but... this form... Y-You have arms in yet..." Papyrus struggled to finish his sentence. MK's eyes turned burning red. Frisk was the one patting his back.

* * *

 

[AFTERMATH]

"Sans..." Papyrus glared at Sans. Back in his room, the demon was drinking mustard and reading a spell book on his bed. "What are you doing here?!"

"i'm here because i feel loved!" Sans replied as he flips a book page. Papyrus couldn't retort to the demon because Papyrus was the one who lets this demon inside in the first place. "At least do it on the floor, demon..."

"sure." And Sans smiled.


End file.
